Duplex scanning disk



Dec. 16, 1930. c. F. JENKINS DUPLEX SCANNING DISK Filed Sept. 6, 1928 Patented Dec. 16, 1930 UNITED STATES PATENT OFFICE CHARLES FRANCIS JENKINS, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO JENKINS LABORATORIES, WASHINGTON, DISTRICT OF COLUMBIA, A CORPORA- TION OF THE DISTRICT OF COLUMBIA DUPLEX SCANNING DISK Application filed September 6, 1928. Serial No. 804,353.

This invention relates to radiovision and television transmitting apparatus, and has for its main object means for greatly increasing the efiiciency of the apparatus.

The method of scanning the object to be transmitted by apoint source of light was disclosed in French Patent No. 390,435, 1908. In this method the light-cell is necessarily illuminated only by the reflected light from the scanned subject.

To increase this efficiency a lens-disk may be employed to project the illuminating spot on the light cell, but it is ditficult to keep the moving spot centered on the light cell.

To overcome this di'fiiculty it has been found desirable to pass both the incident and the reflected light through the same scanning disk.

With this and other objects in view, the invention consists of the novel combination of parts herein disclosed, and particularly pointed out in the claims. 7

In the schematic drawings Figure 1 is an elevation of the light-source side of the disk; Figure 2 an elevation from the light-cell side; Figure 3 a large-aperture scanning disk with lenses over each aperture; and Figure 4 a scanning disk having elementary area apertures therein.

In the figures, A is a source of light; B a mirror for turning the direction of the light beam through the lenses of scanning disk C; D a large lens located in alignment with the light comin through the scanning disk; E an object to e scanned; F a second scanning disk having elementary apertures therein; G a lens lying between this apertured-disk and the light cell H. The lenses on disk C might, if desired, be arranged in a full or partial additional spiral turn. v

Assuming the disks to be put into rotation, a spot of light from the source A is swept across subject E transversely and from top to bottom; and its reflection received on cell H after passing through a lens on disk C at diametrically opposite the moving lens which produces the scanning.

This comes about in spite of the fact that one .radius of the disk is going down and the opposite radius is going up, because the equivalent focus of lens D and lenses on disk cause a reversal of light movement beyond the point K. I

, Absolutely perfect synchronism is attained, however, because the light projected through a lens of one edge of disk C is reflected to the cell through a lens on exactly greatly increased the efiiciency of this method of subject scanning.

What I claim, is

1. In spot scanning of electrically transmitted subjects, the combination of a rotatable scanning disk common to both spot illumination and spot cell-pickup; a source of light from which light is passed through said scanning disk; a disk having apertures in alignment with the scanning elements of said scanning disk and a light-sensitive cell upon which light from the source tallsv after passing through the said scanning disks.

2. In spot scanning of electrically transmitted subjects, the combination of a rotatable scanning member common to both spot illumination and spot cell-pickup; a source of light from which light is passed through mately greater than the space between scanning apertures.

4. In s ot scanning of electrically transmitted sulijects, the combination of a rotatable scanning member; a light-sensitive cell located to receive light passing through said scanning member; and a lens approximately greater than the space between said scanning member and the cell, lying between and in alignment with the cell and scanning member working apertures.

5. The method of scannin which comprises rotating an analyzing device between a light source and an object to expose the said object to a moving spot of light, positioning a light sensitive device in the path of the reflected rays, said reflected rays also assing through said analyzing device and limiting the area of the reflected beam reaching said light sensitive device through said member, by passing the reflected beam through an apertured mask between the analyzing device and the light sensitive device.

6. The method of scannin which comprises projecting a light beam t rough a large apertured scanning device on to an object to be scanned, said scanning device being positioned to permit the rays reflected from said object to pass through a large aperture therein different from the aperture through which the projected rays are passed, and rotating a shutter between said scanning device and a light sensitive device to restrict the area of the reflected beam passing through the large apertures of the scanning device.

7. In a scanning system comprising a source of light, a large apertured scanning member between said source and an object to be scanned and a small apertured scanning member between said first scanning member and the light sensitive device.

8. A scanning system comprising a rotating scanning device having large aperture therein, means for projecting a scanning beam through one aperture of said device onto an object to be scanned, the light reflected from said object passing through another aperture on said disk on the opposite edge thereof and means for projecting the rays passing through said other aperture onto a light sensitive device.

9. A scanning system according to claim 8 in which the large apertures are provided with lenses.

10. A scanning system according to claim 8 in which a small apertured scanning member is rotated between the large apertured scanning member and the light senistive device.

11. A scanning system comprising a light sensitive device, an object whose image is to be transmitted, a first large apertured scann ng member, a second small apertured scanmug member, both members being positioned CHARLES FRANCIS JENKINS.

= DISCLAIM ER 1,785,262.Ohdrles l mnmjsv Jenkins, Washington, D. C. DUPLEX SGANNING DISK. Patent dated December 16, 1930.- Disclaimer filed August 16, 1934, by the assignee, Radio Corporation of America. v

Hereb enters this disclaimer to that part of the claim in said specification which is in the fo owing words, to wit:

8. A scanning system comprising a-rotating scanning device having large aperture therein, means for projecting a scanning beam through one aperture of said device onto an object to be scanned, the light reflected from'said object passing through another aperture on said disk on' the opposite edge thereof and means for projecting the rays passing through said other aperture onto a light sensitive device.

[Ofiic'icl Gazette September.11, 1934.] 

